<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>[287151] branches/safari-612-branch/Source/WebCore</title>
</head>
<body>

<style type="text/css"><!--
#msg dl.meta { border: 1px #006 solid; background: #369; padding: 6px; color: #fff; }
#msg dl.meta dt { float: left; width: 6em; font-weight: bold; }
#msg dt:after { content:':';}
#msg dl, #msg dt, #msg ul, #msg li, #header, #footer, #logmsg { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt;  }
#msg dl a { font-weight: bold}
#msg dl a:link    { color:#fc3; }
#msg dl a:active  { color:#ff0; }
#msg dl a:visited { color:#cc6; }
h3 { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt; font-weight: bold; }
#msg pre { overflow: auto; background: #ffc; border: 1px #fa0 solid; padding: 6px; }
#logmsg { background: #ffc; border: 1px #fa0 solid; padding: 1em 1em 0 1em; }
#logmsg p, #logmsg pre, #logmsg blockquote { margin: 0 0 1em 0; }
#logmsg p, #logmsg li, #logmsg dt, #logmsg dd { line-height: 14pt; }
#logmsg h1, #logmsg h2, #logmsg h3, #logmsg h4, #logmsg h5, #logmsg h6 { margin: .5em 0; }
#logmsg h1:first-child, #logmsg h2:first-child, #logmsg h3:first-child, #logmsg h4:first-child, #logmsg h5:first-child, #logmsg h6:first-child { margin-top: 0; }
#logmsg ul, #logmsg ol { padding: 0; list-style-position: inside; margin: 0 0 0 1em; }
#logmsg ul { text-indent: -1em; padding-left: 1em; }#logmsg ol { text-indent: -1.5em; padding-left: 1.5em; }
#logmsg > ul, #logmsg > ol { margin: 0 0 1em 0; }
#logmsg pre { background: #eee; padding: 1em; }
#logmsg blockquote { border: 1px solid #fa0; border-left-width: 10px; padding: 1em 1em 0 1em; background: white;}
#logmsg dl { margin: 0; }
#logmsg dt { font-weight: bold; }
#logmsg dd { margin: 0; padding: 0 0 0.5em 0; }
#logmsg dd:before { content:'\00bb';}
#logmsg table { border-spacing: 0px; border-collapse: collapse; border-top: 4px solid #fa0; border-bottom: 1px solid #fa0; background: #fff; }
#logmsg table th { text-align: left; font-weight: normal; padding: 0.2em 0.5em; border-top: 1px dotted #fa0; }
#logmsg table td { text-align: right; border-top: 1px dotted #fa0; padding: 0.2em 0.5em; }
#logmsg table thead th { text-align: center; border-bottom: 1px solid #fa0; }
#logmsg table th.Corner { text-align: left; }
#logmsg hr { border: none 0; border-top: 2px dashed #fa0; height: 1px; }
#header, #footer { color: #fff; background: #636; border: 1px #300 solid; padding: 6px; }
#patch { width: 100%; }
#patch h4 {font-family: verdana,arial,helvetica,sans-serif;font-size:10pt;padding:8px;background:#369;color:#fff;margin:0;}
#patch .propset h4, #patch .binary h4 {margin:0;}
#patch pre {padding:0;line-height:1.2em;margin:0;}
#patch .diff {width:100%;background:#eee;padding: 0 0 10px 0;overflow:auto;}
#patch .propset .diff, #patch .binary .diff  {padding:10px 0;}
#patch span {display:block;padding:0 10px;}
#patch .modfile, #patch .addfile, #patch .delfile, #patch .propset, #patch .binary, #patch .copfile {border:1px solid #ccc;margin:10px 0;}
#patch ins {background:#dfd;text-decoration:none;display:block;padding:0 10px;}
#patch del {background:#fdd;text-decoration:none;display:block;padding:0 10px;}
#patch .lines, .info {color:#888;background:#fff;}
--></style>
<div id="msg">
<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/287151">287151</a></dd>
<dt>Author</dt> <dd>alancoon@apple.com</dd>
<dt>Date</dt> <dd>2021-12-16 12:41:57 -0800 (Thu, 16 Dec 2021)</dd>
</dl>

<h3>Log Message</h3>
<pre>Apply patch. rdar://problem/86505382</pre>

<h3>Modified Paths</h3>
<ul>
<li><a href="#branchessafari612branchSourceWebCoreChangeLog">branches/safari-612-branch/Source/WebCore/ChangeLog</a></li>
<li><a href="#branchessafari612branchSourceWebCoreplatformScrollControllerh">branches/safari-612-branch/Source/WebCore/platform/ScrollController.h</a></li>
<li><a href="#branchessafari612branchSourceWebCoreplatformmacScrollControllermm">branches/safari-612-branch/Source/WebCore/platform/mac/ScrollController.mm</a></li>
</ul>

</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchessafari612branchSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/safari-612-branch/Source/WebCore/ChangeLog (287150 => 287151)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-612-branch/Source/WebCore/ChangeLog      2021-12-16 20:40:45 UTC (rev 287150)
+++ branches/safari-612-branch/Source/WebCore/ChangeLog 2021-12-16 20:41:57 UTC (rev 287151)
</span><span class="lines">@@ -1,3 +1,27 @@
</span><ins>+2021-12-16  Alan Coon  <alancoon@apple.com>
+
+        Apply patch. rdar://problem/86505382
+
+    2021-12-16  Simon Fraser  <simon.fraser@apple.com>
+
+            rdar://86505382 ([root] StarE21E179 / J314c : Slight but noticeable J-shaped "wobble" at tail end of sm-med scrolls)
+
+            Branch patch reviewed by Tim Horton. 
+
+            During momentum scrolling, we axis-lock on a per-event basis by zeroing out the smaller
+            of the X and Y deltas. This is a problem for slightly diagonal scrolls, where, towards
+            the tail, in a Y-biased scroll we can get individual events whose X delta is later than
+            their Y delta.
+
+            To fix this, use the same axis locking for all the events in a gesture, based on the
+            scrollingVelocity() of the last fingers-down event. This velocity is not strictly
+            X- or Y-locked; it can contain both X and Y deltas for strongly diagonal gestures,
+            but that's what we want.
+
+            * platform/ScrollController.h:
+            * platform/mac/ScrollController.mm:
+            (WebCore::ScrollController::handleWheelEvent):
+
</ins><span class="cx"> 2021-12-13  Alan Coon  <alancoon@apple.com>
</span><span class="cx"> 
</span><span class="cx">         Cherry-pick r286907. rdar://problem/86307593
</span></span></pre></div>
<a id="branchessafari612branchSourceWebCoreplatformScrollControllerh"></a>
<div class="modfile"><h4>Modified: branches/safari-612-branch/Source/WebCore/platform/ScrollController.h (287150 => 287151)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-612-branch/Source/WebCore/platform/ScrollController.h    2021-12-16 20:40:45 UTC (rev 287150)
+++ branches/safari-612-branch/Source/WebCore/platform/ScrollController.h       2021-12-16 20:41:57 UTC (rev 287151)
</span><span class="lines">@@ -217,6 +217,7 @@
</span><span class="cx">     FloatSize m_overflowScrollDelta;
</span><span class="cx">     FloatSize m_stretchScrollForce;
</span><span class="cx">     FloatSize m_momentumVelocity;
</span><ins>+    FloatSize m_lastActivePhaseVelocity;
</ins><span class="cx"> 
</span><span class="cx">     bool m_inScrollGesture { false };
</span><span class="cx">     bool m_momentumScrollInProgress { false };
</span></span></pre></div>
<a id="branchessafari612branchSourceWebCoreplatformmacScrollControllermm"></a>
<div class="modfile"><h4>Modified: branches/safari-612-branch/Source/WebCore/platform/mac/ScrollController.mm (287150 => 287151)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-612-branch/Source/WebCore/platform/mac/ScrollController.mm       2021-12-16 20:40:45 UTC (rev 287150)
+++ branches/safari-612-branch/Source/WebCore/platform/mac/ScrollController.mm  2021-12-16 20:41:57 UTC (rev 287151)
</span><span class="lines">@@ -125,6 +125,9 @@
</span><span class="cx">         return true;
</span><span class="cx">     }
</span><span class="cx"> 
</span><ins>+    if (wheelEvent.phase() == PlatformWheelEventPhase::Changed)
+        m_lastActivePhaseVelocity = -wheelEvent.scrollingVelocity();
+
</ins><span class="cx">     bool isMomentumScrollEvent = (wheelEvent.momentumPhase() != PlatformWheelEventPhase::None);
</span><span class="cx">     if (m_ignoreMomentumScrolls && (isMomentumScrollEvent || m_isAnimatingRubberBand)) {
</span><span class="cx">         if (wheelEvent.momentumPhase() == PlatformWheelEventPhase::Ended) {
</span><span class="lines">@@ -162,21 +165,28 @@
</span><span class="cx">     deltaX += eventCoalescedDeltaX;
</span><span class="cx">     deltaY += eventCoalescedDeltaY;
</span><span class="cx"> 
</span><ins>+    auto momentumPhase = wheelEvent.momentumPhase();
+    // If we are starting momentum scrolling then do some setup.
+    if (!m_momentumScrollInProgress && (momentumPhase == PlatformWheelEventPhase::Began || momentumPhase == PlatformWheelEventPhase::Changed))
+        m_momentumScrollInProgress = true;
+
</ins><span class="cx">     // Slightly prefer scrolling vertically by applying the = case to deltaY
</span><span class="cx">     // FIXME: Use wheelDeltaBiasingTowardsVertical().
</span><del>-    if (fabsf(deltaY) >= fabsf(deltaX))
-        deltaX = 0;
-    else
-        deltaY = 0;
</del><ins>+    if (m_momentumScrollInProgress) {
+        // Use the same axis locking for the duration of a momentum scroll.
+        if (!m_lastActivePhaseVelocity.width())
+            deltaX = 0;
+        else if (!m_lastActivePhaseVelocity.height())
+            deltaY = 0;
+    } else {
+        if (fabsf(deltaY) >= fabsf(deltaX))
+            deltaX = 0;
+        else
+            deltaY = 0;
+    }
</ins><span class="cx"> 
</span><span class="cx">     bool shouldStretch = false;
</span><span class="cx"> 
</span><del>-    PlatformWheelEventPhase momentumPhase = wheelEvent.momentumPhase();
-
-    // If we are starting momentum scrolling then do some setup.
-    if (!m_momentumScrollInProgress && (momentumPhase == PlatformWheelEventPhase::Began || momentumPhase == PlatformWheelEventPhase::Changed))
-        m_momentumScrollInProgress = true;
-
</del><span class="cx">     auto timeDelta = wheelEvent.timestamp() - m_lastMomentumScrollTimestamp;
</span><span class="cx">     if (m_inScrollGesture || m_momentumScrollInProgress) {
</span><span class="cx">         if (m_lastMomentumScrollTimestamp && timeDelta > 0_s && timeDelta < scrollVelocityZeroingTimeout) {
</span></span></pre>
</div>
</div>

</body>
</html>